Coal Trading (Tables) (Coal Trading [Member])

6 Months Ended

Jun. 30, 2014

Coal Trading [Member]

Coal Trading [Line Items]

Trading revenue by type of instrument

Trading revenues recognized during the three and six months ended June 30, 2014 and 2013 were as follows:

	Three Months Ended						Six Months Ended
	June 30,						June 30,
Trading Revenues by Type of Instrument	2014			2013			2014			2013
	(Dollars in millions)
Commodity futures, swaps and options	$	22.7		$	34.9		$	58.3		$	85.9
Physical commodity purchase/sale contracts	(12.4		)	(38.3		)	(27.0		)	(63.4		)
Total trading revenues	$	10.3		$	(3.4	)	$	31.3		$	22.5

Fair value of assets and liabilities from coal trading activities and related balance sheet offsetting

The fair value of assets and liabilities from coal trading activities presented on a gross and net basis as of June 30, 2014 and December 31, 2013 is set forth below:

Affected line item in the condensed consolidated balance sheets	Gross Amounts of Recognized Assets (Liabilities)			Gross Amounts Offset in the Condensed Consolidated Balance Sheets			Variation margin (held) posted (1)			Net Amounts of Assets (Liabilities) Presented in the Condensed Consolidated Balance Sheets
	(Dollars in millions)
	Fair Value as of June 30, 2014
Assets from coal trading activities, net	$	430.2		$	(345.4	)	$	(34.0	)	$	50.8
Liabilities from coal trading activities, net	(359.8		)	345.4			—			(14.4		)
Total, Net	$	70.4		$	—		$	(34.0	)	$	36.4
	Fair Value as of December 31, 2013
Assets from coal trading activities, net	$	418.8		$	(324.7	)	$	(58.0	)	$	36.1
Liabilities from coal trading activities, net	(332.7		)	324.7			1.9			(6.1		)
Total, Net	$	86.1		$	—		$	(56.1	)	$	30.0

⁽¹⁾  Approximately $15 million and $42 million of the net variation margin held at June 30, 2014 and December 31, 2013, respectively, related to cash flow hedges.

Fair value coal trading net assets (liabilities) measured on recurring basis

The following tables set forth the hierarchy of the Company’s net financial asset (liability) coal trading positions for which fair value is measured on a recurring basis as of June 30, 2014 and December 31, 2013:

	June 30, 2014
	Level 1		Level 2			Level 3		Total
	(Dollars in millions)
Commodity futures, swaps and options	$	—	$	37.7		$	—	$	37.7
Physical commodity purchase/sale contracts	—		(3.9		)	2.6		(1.3		)
Total net financial assets	$	—	$	33.8		$	2.6	$	36.4

	December 31, 2013
	Level 1		Level 2		Level 3		Total
	(Dollars in millions)
Commodity futures, swaps and options	$	—	$	26.4	$	—	$	26.4
Physical commodity purchase/sale contracts	—		1.5		2.1		3.6
Total net financial assets	$	—	$	27.9	$	2.1	$	30.0

Schedule of quantitative unobservable inputs, physical commodity purchase/sale contracts

The following table summarizes the quantitative unobservable inputs utilized in the Company's internally-developed valuation models for physical commodity purchase/sale contracts classified as Level 3 as of June 30, 2014:

	Range				Weighted
Input	Low		High		Average
Quality adjustments	1	%	8	%	7	%
Location differentials	17	%	64	%	37	%

Change in the Company's recurring Level 3 net financial assets

The following table summarizes the changes in the Company’s recurring Level 3 net financial assets:

	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2014			2013			2014			2013
	(Dollars in millions)
Beginning of period	$	2.2		$	1.4		$	2.1		$	5.2
Total net gains (losses) realized/unrealized:
Included in earnings	1.5			(0.3		)	3.3			(4.4		)
Settlements	(1.1		)	0.2			(2.8		)	0.5
End of period	$	2.6		$	1.3		$	2.6		$	1.3

Changes in unrealized gains (losses) relating to Level 3 net financial assets

The following table summarizes the changes in net unrealized gains (losses) relating to Level 3 net financial assets held both as of the beginning and the end of the period:

	Three Months Ended					Six Months Ended
	June 30,					June 30,
	2014		2013			2014		2013
	(Dollars in millions)
Changes in net unrealized gains (losses) (1)	$	1.2	$	(2.8	)	$	0.3	$	(2.6	)

⁽¹⁾  Within the unaudited condensed consolidated statements of operations and unaudited condensed consolidated statements of comprehensive income for the periods presented, unrealized gains and losses from Level 3 items are combined with unrealized gains and losses on positions classified in Level 1 or 2, as well as other positions that have been realized during the applicable periods.

Schedule of future realization of the Company's trading portfolio

As of June 30, 2014, the timing of the estimated future realization of the value of the Company’s trading portfolio was as follows:

	Percentage of
Year of Expiration	Portfolio Total
2014	68	%
2015	19	%
2016	10	%
2017	2	%
2018	1	%
	100	%